New study explains why superconductivity takes place in graphene
Graphene, a single sheet of carbon atoms, has many extreme electrical and mechanical properties. Two years ago, researchers showed how two sheets laid on top of each other and twisted at just the right angle can become superconducting, so that the material loses its electrical resistivity. New work explains why this superconductivity happens in a surprisingly high temperature.
Researchers at Aalto University and the University of Jyv盲skyl盲 showed that graphene can be a superconductor at a much higher temperature than expected, due to a subtle quantum mechanics effect of graphene鈥檚 electrons. The results were published in Physical Review . The findings were highlighted in by the American Physical Society, and looks set to spark lively discussion in the physics community.
The discovery of the superconducting state in twisted bilayer graphene was selected as the , and it spurred an intense debate among physicist about the origin of superconductivity in graphene. Although superconductivity was found only at a few degrees above the absolute zero of temperature, uncovering its origin could help understanding high-temperature superconductors and allow us to produce superconductors that operate near room temperature. Such a discovery has been considered one of the 鈥渉oly grails鈥 of physics, as it would allow operating computers with radically smaller energy consumption than today.
The new work came from a collaboration between P盲ivi T枚rm盲鈥檚 group at Aalto University and Tero Heikkil盲鈥檚 group at the University of Jyv盲skyl盲. Both have studied the types of unusual superconductivity most likely found in graphene for several years.
鈥淭he geometric effect of the wave functions on superconductivity was discovered and studied in my group in several model systems. In this project it was exciting to see how these studies link to real materials鈥, says the main author of the work, Aleksi Julku from Aalto University. 鈥淏esides showing the relevance of the geometric effect of the wave functions, our theory also predicts a number of observations that the experimentalists can check鈥, explains Teemu Peltonen from the University of Jyv盲skyl盲.
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Further information:
Aleksi Julku, Aalto University Aleksi.Julku@aalto.fi
Teemu Peltonen, University of Jyv盲skyl盲 Teemu.J.Peltonen@student.jyu.fi
Long Liang, Aalto University, Long.Liang@su.se
Tero Heikkil盲, University of Jyv盲skyl盲, Tero.T.Heikkila@jyu.fi, tel. +358408054804
P盲ivi T枚rm盲, Aalto University, Paivi.Torma@aalto.fi, tel., +358503826770
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